1-Thiadiazolyl-5-carbamoyloxyimidazolidinones

ABSTRACT

WHEREIN X is selected from the group consisting of alkyl, halogen, haloalkyl and alkoxy, and n is an integer from 0 to 5.   D R A W I N G This invention discloses new compounds of the formula   wherein R1 is selected from the group consisting of alkyl, alkenyl, haloalkyl, alkoxy, alkylthio, alkylsufonyl and alkylsulfinyl; R2 is alkyl; R3 is selected from the group consisting of hydrogen and alkyl; Y is selected from the group consisting of oxygen and sulfur; and R4 is selected from the group consisting of hydrogen, alkyl, cycloalkyl and

United States Patent [191 Krenzer Dec. 9, 1975 l 5 l-THIADlAZOLYL-S- C ARBAMOYLOXYIMIDAZOLIDINONES [75] Inventor: John Krenzer, Oak Park, Ill.

[73] Assignee: Velsicol Chemical Corporation, Chicago, Ill.

[22] Filed: Feb. 15, 1974 [21] Appl. No.: 442,934

Related US. Application Data [63] Continuation-impart of Ser. No. 425,272, Dec, 26.

1973, abandoned.

[52] US. Cl. 260/3063 D; 7 H90 [51] Int. Cl? C07D 513/02 [58] Field of Search 260/3068 D [56] References Cited UNITED STATES PATENTS 3,759,939 9/l973 Metzger et al 260/3063 D Primary Examiner-R. J. Gallagher Attorney, Agent, or FirmRobert J. Schwarz; Dietmar H. Olesch [57] ABSTRACT This invention discloses new compounds of the formula wherein R is selected from the group consisting of alkyl, alkenyl, haloalkyl, alkoxy, alkylthio, alkylsufonyl and alkylsulfinyl; R is alkyl; R is selected from the group consisting of hydrogen and alkyl; Y is selected from the group consisting of oxygen and sulfur; and R is selected from the group consisting of hydrogen, alkyl, cycloalkyl and wherein X is selected from the group consisting of alkyl, halogen. haloalkyl and alkoxy, and n is an integer from 0 to 5.

8 Claims, No Drawings l-Tl-l[ADlAZOLYL--CARBAMOYLOX- YIMIDAZOLIDINONES This application is a continuation-in-part of copending application Ser. No. 428,272, filed Dec. 26, 1973, now abandoned.

This invention relates to new compositions of matter and more particularly relates to new chemical compounds of the formula wherein R is selected from the group consisting of alkyl, alkenyl, haloalkyl, alkoxy, alkylthio, alkylsulfonyl and alkylsulfinyl; R is alkyl; R is selected from the group consisting of hydrogen and alkyl; Y is selected from the group consisting of oxygen and sulfur; and R is selected from the group consisting of hydrogen, alkyl, cycloalkyl and wherein X is selected from the group consisting of alkyl, halogen, haloalkyl andalkoxy, and n is an integer from 0 to 5.

The compounds of this invention are unexpectedly useful as herbicides.

in a preferred embodiment of the present invention R is selected from the group consisting of lower alkyl, lower alkenyl, lower haloalkyl, lower alkoxy, lower alkylthio, lower alkylsulfonyl and lower alkylsulfinyl; R is lower alkyl; R is selected from the group consisting of hydrogen and lower alkyl; and R is selected from the group consisting of hydrogen, lower alkyl, cycloalkyl of from 3 to 7 carbon atoms, and

wherein X is selected from the group consisting of lower alkyl, halogen, lower haloalkyl and lower alkoxy, and n is an integer from 0 to 3.

The term lower as used herein designates a straight or branched carbon chain of up to six carbon atoms.

The compounds of the present invention wherein one of R or R is hydrogen can be prepared by reacting a compound of the formula HI N R (ll) wherein R and R are as heretofore described, with an isocyanate or isothiocyanate of the formula Y=C=NR (Ill) wherein Y and R are as heretofore described with the exclusion of hydrogen. This reaction can be effected by combining the compound of formula ll with about an equimolar or slight excess molar amount of the isocyanate of formula III at room temperature and in the presence of a catalytic amount of triethylamine. An inert organic solvent can be used if desirable. The reaction mixture can be stirred at room temperature or at elevated temperatures if the reaction proceeds slowly and then let stand for a period of up to about 1 hour to ensure completion of the reaction. After this time excess isocyanate if used can be removed by vacuum stripping to yield the desired product which can be used as such or can be further purified by conventional means such as washing, recrystallizing and the like.

The compounds of the present invention wherein neither R nor R is hydrogen can be prepared by reacting a compound of formula ll as heretofore described with a carbamoyl chloride of the formula Cl-C-N R (IV) wherein Y, R and R are as heretofore described except that neither R nor R is hydrogen. This reaction can be effected by combining about equimolar amounts of the compounds of formulae ll and IV in an inert organic solvent such as toluene or xylene in the presence of an acid acceptor such as a tertiary amine. The reaction mixture can then be heated at reflux for a period of from about V2 to about 4 hours. After this time the reaction mixture can be filtered to remove acid acceptor salt and can then be stripped of solvent under vacuum to yield the desired product as the residue. This product can be used as such or can be further purified by washing, recrystallizing and the like.

The compounds of the present invention wherein both R and R are hydrogen can be prepared by reacting a compound of formula ll with potassium cyanate or potassium thiocyanate in the presence of concentrated acetic acid. This reaction can be effected by dispersing the compound of formula 11 in a reaction medium containing percent acetic acid and 10 percent water. Powdered potassium cyanate can then be incrementally added with stirring at room temperature. After the addition is completed stirring can be continued for a period of from xi to 2 hours to ensure completion of the reaction. Water can then be added to precipitate the product. After this time the desired product wherein R and R are as heretofore described, in a dilute, aqueous, acidic reaction medium for a period of about to about 60 minutes. Temperatures of from about 70C to the reflux temperature of the reaction mixture can be utilized. The reaction medium can comprise a dilute aqueous inorganic acid such as hydrochloric acid at a concentration of from about 0.5 to about 5 percent. Upon completion of the reaction the desired product can be recovered as a precipitate by cooling the reaction mixture. This product can be used as such or can be further purified by conventional means such as recrystallization and the like.

The compounds of formula V can be prepared by reacting a molar amount of an isocyanate dimer of the formula wherein R is as heretofore described, with about two molar amounts of a dimethyl acetal of the formula O vn wherein R is as heretofore described. This reaction can be effected by heating a mixture of the isocyanate dimer and the acetal in an inert organic reaction medium such as benzene at the reflux temperature of the reaction mixture. Heating at reflux can be continued for a period of from about 2 to about 30 minutes to ensure completion of the reaction. After this time the desired product can be recovered upon evaporation of the reaction medium and can be used as such or can be further purified by standard techniques in the art.

The isocyanate dimer of formula VI can be prepared by reacting a thiadiazole of the formula all l1...

(VIII) uct can then be recovered by filtration, if formed as a precipitate, or upon evaporation of the organic solvent used if soluble therein. This product can be used as such or can be further purified as desired.

Exemplary thiadiazoles of formula VIII useful for preparing the compounds of the present invention are:

5-methyl2-aminol ,3 ,4-thiadiazole, 5-ethyl-2- amino-l ,3 ,4-thiadiazole, S-propyl-Z-amino-l ,3 ,4- thiadiazole, 5-t-butyl-2-amino-l,3,4-thiadiazole, 5- allyl-2-aminol ,3 ,4-thiadiazole, 5-pent-3-enyl-2- amino-1,2,3-thiadiazole, 5-chloromethyl-2-amino- 1,3 ,4-thiadiazole, S-fi-chloroethyl-Z-aminol ,3 ,4- thiadiazole, 5-'y-chloropropyl-2-amino-l ,3 ,4- thiadiazole, 5 -trichloromethyl-2-amino-l ,3 ,4 thiadiazole, 5-trifluoromethyl-2-amino- I ,3 ,4- thiadiazole, S-methoxy-Z-amino-l,3,4-thiadiazole, 5- ethoxy-2-amino-l ,3,4-thiadiazole, S-propoxy-Z-aminol ,2,4-thiadiazole, S-butyloxy-Z-amino- 1,3 ,4thiadiazole S-hexyloxy-Z-amino- I ,3 ,4- thiadiazole, 5-methylthio-2-amino-l,3,4-thiadiaz0le, 5-ethylthio-2-aminol ,2,3-thiadiazole, S-propylthio-Z- amino-l ,3 ,4-thiadiazole, Sbutylthio-Z-amino- I ,3 ,4- thiadiazole, 5 -methylsulfonyl-2-amino-l ,3 ,4- thiadiazole, 5-ethylsulfonyl-2-amino-l,3,4-thiadiazole, 5-butylsulfonyl-2-amino-l,3,4-thiadiazole, S-methylsulfinyl-2-amino-l ,3,4-thiadiazole, S-ethyIsulfinyI-Z- amino-1,3 ,4thiadiazole, Spropylsulfinyl-Z-amino-1,3,4- thiadiazole, -butylsulfinyl-2-amino-I ,3 ,4-thiadiazole, and the like.

Exemplary suitable acetals of formula Vll for preparing the compounds of this invention are the dimethyl acetal of 2-methylaminoacetaldehyde, the dimethyl acetal of 2-ethyl-aminoacetaldehyde, the dimethyl acetal of Z-propylaminoacetaldehyde, the dimethyl acetal of Z-butylaminoacetaldehyde, the dimethyl acetal of 2- pentylaminoacetaldehyde and the dimethyl acetal of 2-hexylaminoacetaldehyde.

Exemplary suitable isocyanates and isothiocyanates of formula [II are methyl isocyanate, ethyl isocyanate, propyl isocyanate, butyl isocyanate, hexyl isocyanate, cyclopropyl isocyanate, cyclobutyl isocyanate, cyclopentyl isocyanate, cyclohexyl isocyanate, cyeloheptyl isocyanate, phenyl isocyanate, Z-methylphenyl isocyanate, 4-ethylphenyl isocyanate, 4butylphenyl isocyanate, 2-chlorophenyl isocyanate, 2,4-dichlorophenyl isocyanate, 4-bromophenyl isocyanate, 4-fluorophenyl isocyanate, 4-chloromethylphenyl isocyanate, 4-trifluoromethylphenyl isocyanate, Z-methoxyphenyl isocyanate, 2-ethoxyphenyl isocyanate, Z-propoxyphenyl isocyanate, 2-methyl-4-chlorophenyl isocyanate, 2- methyoxy-3,6-dichlorophenyl isocyanate, methyl isothiocyanate, ethyl isothiocyanate, propyl isothiocyanate, butyl isothiocyanate, hexyl isothiocyanate, cyclopropyl isothiocyanate, cyclobutyl isothiocyanate, cyclopentyl isothiocyanate, cyclohexyl isothiocyanate, cyeloheptyl isothiocyanate, phenyl isothiocyanate, 2- methylphenyl isothiocyanate, 4-ethylphenyl isothiocyanate, 4-butylphenyl isothiocyanate, 2-chlorophenyl isothiocyanate, 2,4-dichlorophenyl isothiocyanate, 4- bromophenyl isothiocyanate, 4-trifluoromethylphenyl isothiocyanate, 2-methoxyphenyl isothiocyanate, 2- ethoxyphenyl isothiocyanate, Z-propoxyphenyl isothiocyanate, 2-methyl-4-chlorophenyl isothiocyanate, 2- methoxy-3,fi-dichlorophenyl isothiocyanate and the like.

Exemplary suitable carbamoyl and thiocarbamoyl chlorides of formula IV are N,N-dimethylcarbamoyl chloride, N,N-diethylcarbamoylchloride, N ,N-

dibutylthiocarbamoyl oyl chloride, N-ethyl-N-cycloheptylcarbamoyl chloride, N-methyl-N-phenylcarbamoyl chloride, N-ethyl- N-phenylcarbamoyl chloride, N-methyl-N-(Z-methylphenyl)carbamoyl chloride, N-methyl-N-(Z-ethylphenyl)carbamoyl chloride, N-methyl-N-(Z-propylphenyl)carbamoyl chloride, N-methyl-N-(4-chlorophenyl)carbamoyl chloride, N-methyl-N-(4-bromophenyl)carbamoyl chloride, N-methyl-N-(Z-methoxyphenyl)carbamoyl chloride, N-methyl-N-(4-trifluoromethylphenyl)carbamoyl chloride, N,N-dimethylthiocarbamoyl chloride, N,N-diethylthiocarbamoyl chloride, N,N-dipropylthiocarbamoyl chloride, N,N- chloride, N,N-dihexylthiocarbamoyl chloride, N-methyl-N-cyclopropylthiocarbamoyl chloride, N-methyl-N-cyclohexylthiocarbamoyl chloride, N-methyl-N-cycloheptylthiocarbamoyl chloride, N-ethyl-N-cycloheptylthiocarbaoyl chloride, N- methyl-N-phenylthiocarbamoyl chloride, N-ethyl-N- phenylthiocarbamoyl chloride, N-methyl-N-(Z-methylphenyl)thiocarbamoyl chloride, N-methyl-N-(Z-ethylphenyl)thiocarbamoyl chloride, N-methyl-N-(2- propylphenyl)thiocarbamoyl chloride, N-methyl-N-(4- chlorophenyl)thiocarbamoyl chloride, N-methyl-N-(4- bromophenyl)thiocarbamoyl chloride, N-methyl-N-( 2- methoxyphenyl)thiocarbamoyl chloride and N-methyl- N-(4-trifluoromethylphenyl)thiocarbamoyl chloride.

The manner in which the compounds of the present invention can be prepared is more specifically illustrated in the following examples.

EXAMPLE 1 Preparation of S-Methyl-l ,3 ,4-thiadiazol-2-yl Isocyanate Dimer A saturated solution of phosgene in ethyl acetate 100 ml) is charged into a glass reaction vessel equipped with a mechanical stirrer. A slurry of S-methyl-2-amino-l,3,4-thiadiazole (40 grams) in ethyl acetate (300 ml) is added to the reaction vessel and the resulting mixture is stirred for a period of about 16 hours, resulting in the formation of a precipitate. The reaction mixture is then purged with nitrogen gas to remove unreacted phosgene. The purged mixture is then filtered to recover the precipitate. The precipitate is then recrystallized to yield the desired product S-methyll,3,4-thiadiazol-2-yl isocyanate dimer.

EXAMPLE 2 Preparation of the Dimethyl Acetal of 2-[ l-Methyl-B-(S-methyl-l ,3 ,4-thiadiazol-2-yl)ureido I acetaldehyde A mixture of S-methyl-l,3,4-thiadiazol-2-yl isocyanate dimer (0.05 mole), the dimethyl acetal of 2- methylaminoacetaldehyde (0.1 mole) and benzene (60 ml) are charged into a glass reaction vessel equipped with a mechanical stirrer and reflux condenser. The reaction mixture is heated at reflux for a period of about minutes. After this time the mixture is stripped of benzene under reduced pressure to yield a solid product as the residue. The residue is then recrystallized to yield the desired product the dimethyl acetal of 2-[1- methyl-3-(5-methyl-l ,3 ,4-thiadiazol-2- yl)ureido]acetaldehyde.

EXAMPLE 3 Preparation of I-(S-Methyl-l ,3,4-thiadiazol-2-yl)-3-methyl-5- hydroxy-l ,3-imidazolidin-2-one The dimethyl acetal of 2-[ l-methyl-3-(S-methyl- 1,3,4-thiadiazol-2-yl)ureido] acetaldehyde 15 grams), water (400 ml) and hydrochloric acid (4 ml) are charged into a glass reaction vessel equipped with a mechanical stirrer thermometer and reflux condenser. The reaction mixture is heated at reflux for a period of about 15 minutes. The reaction mixture is then filtered while hot and the filtrate is cooled to form a precipitate. The precipitate is recovered by filtration, is dried and is recrystallized to yield the desired product l-(5- methyl-l ,3,4-thiodiazol-2-yl)-3-methyl-5hydroxy-l ,3- imidazolidin-2-one.

EXAMPLE 4 Preparation of I-(S-Methyl-l ,3,4-thiadiazol-2-yl)-3-methyl-5-(N- methylcarbamoyloxy)-l ,3-imidazolidin-2-one l-(S-Methyl-l ,3,4-thiadiazol-2-yl)-3-methyl-5- hydroxy-l ,B-imidazolidin-Z-one (0.05 mole) and methyl isocyanate (3.5 ml; 0.06 mole) are charged into a glass reaction vessel equipped with a mechanical stirrer. The mixture is stirred and triethylamine I drop) is added. The reaction mixture is then allowed to stand for a period of about 1 hour. After this time the product is washed with hexane to yield the desired product 1- (S-methyl-l ,3,4-thiadiazol-2-yl)-3-methyl-5-(N- methylcarbamoyloxy)-l ,3-imidazolidin-2-one.

EXAMPLE 5 Preparation of S-t-Butyl-l ,3,4-thiadiazol-2-yl lsocyanate Dimer A saturated solution of phosgene in ethyl acetate (100 ml) was charged into a glass reaction vessel equipped with a mechanical stirrer. A slurry of S-tbutyl-Z-amino-l ,3,4-thiadiazole (10 grams) in ethyl acetate (300 ml) was added to the reaction vessel and the resulting mixture was stirred for a period of about 16 hours resulting in the formation of a precipitate. The reaction mixture was then purged with nitrogen gas to remove unreacted phosgene. The purged mixture was then filtered to recover the desired product 5-t-butyl- 1,3 ,4-thiadiazol-2-yl-isocyanate dimer as a solid having a melting point of 26] to 263C.

EXAMPLE 6 Preparation of the Dimethyl Acetal of 2-[ l -Methyl-3-( S-t-butyl-l ,3 ,4-thiadiazol-2- yl)ureido]acetaldehyde A mixture of S-t-butyl-l,3,4-thiadiazol-2-yl isocyanate dimer (6 grams), the dimethyl acetal of 2- methylaminoacetaldehyde (3.9 grams) and benzene (50 ml) was charged into a glass reaction flask equipped with a mechanical stirrer and reflux condenser. The reaction mixture was heated at reflux, with stirring for a period of about 5 minutes. After this time the reaction mixture was stripped of benzene to yield an oil which solidified upon standing. The resulting solid was then recrystallized from pentane to yield the desired product the dimethyl acetal of 2-[l-methyl-3- (S-t-butyll ,3 ,4-thiadiazol-2-yl )ureido]-acetaldehyde having a melting point of -82C.

EXAMPLE 7 Preparation of l-(-t-Butyl-1,3 ,4-thiadiazol-2-yl)-3methyl-5- hydroxyl ,3-imidazolidin-2-one The dimethyl acetal of 2-[l-methyl-3-(5-t-butyll,3,4-thiadiazol-2-yl)ureido] acetaldehyde (16 grams), concentrated hydrochloric acid (It) ml) and water (500 ml) were charged into a glass reaction vessel equipped with a mechanical stirrer, thermometer and reflux condenser. The reaction mixture was heated at reflux for a period of about 15 minutes. The reaction mixture was filtered while hot and the filtrate was then cooled, resulting in the formation of a precipitate. The precipitate was recovered by filtration, dried and was recrystallized from a benzene-hexane mixture to yield the desired product 1-(5-t-butyl-l ,3,4-thiadiazol-2-yl)- 3-methyl-5-hydroxy-1,3-imidazolidin-2-one having a melting point of 133 to 134C.

EXAMPLE 8 Preparation of 1 -(5-t-Buty1-l ,3,4-thiadiazol-2-yl )-3-methyl-5-( N- methylcarbamoyloxy)-l ,3-imidazolin-2-one l-(5-tButyl-1,3,4 thiadiazol-2-yl)-3-methyl-5- hydroxy-l,3-imidazolin-2-one (4 grams) and methyl isocyanate (5 ml) were charged into a glass reaction vessel equipped with a mechanical stirrer. The mixture was stirred until homogeneous and triethylamine (1 drop) was added thereto. The reaction mixture was then allowed to stand for 1 hour. The reaction mixture was then stripped of excess isocyanate and the remaining solid was recrystallized from isopropyl alcohol to yield the desired product 1-(5-t-butyl-1,3,4-thiadiazol- 2-y1)-3-methyl-5-(N-methylcarbamoyloxy)-1,3- imidazolidin-Z-one having a melting point of 195 to 198C.

EXAMPLE 9 Preparation of S-Trifluoromethyl-l ,3,4-thiadiazol-2-y1 lsocyanate Dimer A saturated solution of phosgene in ethyl acetate (100 ml) was charged into a glass reaction vessel equipped with a mechanical stirrer. A slurry of S-trifluoromethyl-2-amino-1,3,4-thiadiazole (45 grams) in ethyl acetate (300 ml) was added to the reaction vessel and the resulting mixture was stirred for a period of about 16 hours resulting in the formation of precipitate. The reaction mixture was then purged with nitrogen gas to remove unreacted phosgene. The purged mixture was filtered to recover 48 grams of a white solid. This solid was recrystallized from dimethyl formamide to yield the desired product 5-trifluoromethyl- 1,3,4-thiadiazol-2-yl isocyanate dimer.

EXAMPLE 10 Preparation of the Dimethyl Acetal of 2-[1-Methyl-3-(Strifluoromethyl-1,3,4-thiadiazol-2- yl)ureido] acetaldehyde A mixture of a S-trifluoromethyl-l,3,4-thiadiazol- 2-yl isocyanate dimer (9.5 grams), the dimethyl acetal of 2-methylaminoacetaldehyde (5.8 grams) and benzene (60 ml) are charged into a glass reaction vessel equipped with a mechanical stirrer and reflux condenser. The reaction mixture is heated at reflux for a period of about minutes. After this time the mixture 5 dimethyl acetal of 2-[l-methyl-3-(5-trifluoromethyl- 1,3,4-thiadiazol-2-yl) ureido] acetaldehyde having a melting point of 101 to 102C.

EXAMPLE 11 Preparation of l-( S-Trifluoromethyl-l ,3,4-thiadiazol-2-yl )-3-methyl- 5-hydroxy-1,3 -imidazo1idin-2-one The dimethyl acetal of 2-[l-methyl-3-(5-trifluoromethyl-l,3,4-thiadiazol-2-yl) ureido] acetaldehyde (15 grams), water (400 ml) and hydrochloric acid (4 ml) were charged into a glass reaction vessel equipped with a mechanical stirrer, thermometer and reflux condenser. The reaction mixture was heated at reflux for a period of about 15 minutes. The reaction mixture was then filtered while hot and the filtrate was cooled resulting in the formation of a precipitate. The precipitate was recovered by filtration, was dried and was recrystallized from an ethyl acetate-hexane mixture to yield the desired product l-(5-trifluoromethyll ,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3- imidazolidin-Z-one having a melting point of 136 to EX A M P LE 1 2 Preparation of 1-(5-Trifluoromethyl-1,3,4-thiadiazol-2-yl)-3methyl-5- (N-methylcarbamoyloxy )-l ,3-imidazolidin-2-one EXAMPLE 13 Preparation of l-(S-Trifluoromethyl-l ,3 ,4-thiadiazol-2-yl )-3-methyl- 5-(N-phenylcarbamoyloxy)-1,3-imidazolidin-2-one l-( S-Trifluoromethyl- 1 ,3 ,4-thiadiazol-2-yl )-3-methyl-S-hydroxy-l,3-imidazolidin-2-one (4 grams) and phenyl isocyanate were charged into a glass reaction vessel. The mixture was stirred until homogeneous and triethylamine (1 drop) was added. The mixture was then allowed to stand for V; hour. After this time the resulting product was washed with hexane and was then recrystallized from an ethyl acetate-heptane mixture to yield the desired product l-(5-trifluoromethyl-1,3,4- thiadiazol-Z-yl)-3-methyl-S-(N-phenylcarbamoyloxy)- 1,3-imidazolidin-2-one having a melting point of 180 to 182C.

EXAMPLE 14 Preparation of S-Methoxy-l,3,4-thiadiazol'2-yl isocyanate Dimer A saturated solution of phosgene in ethyl acetate ml) is charged into a glass reaction vessel equipped with a mechanical stirrer. A slurry of 5- methoxy-2-amino-l ,3,4-thiadiazole (40 grams) in ethyl acetate (300 ml) is added to the reaction vessel and the resulting mixture is stirred for a period of about l6 hours, resulting in the formation of a precipitate. The reaction mixture is then purged with nitrogen gas to remove unreacted phosgene. The purged mixture is then filtered to recover the precipitate. The precipitate is then recrystallized to yield the desired product methoxy-l ,3,4-thiadiazol-2-yl isocyanate dimer.

EXAMPLE [5 Preparation of the Dimethyl Acetal of 2-[ l-Ethyl-3-(5-methoxy-l ,3,4-thiadiazol-2-yl) ureido] acetaldehyde A mixture of 5-methoxyl,3,4-thiadiazol-2-yl isocyanate dimer (0.05 mole), the dimethyl acetal of 2- ethylaminoacetaldehyde (0.1 mole) and benzene (60 ml) are charged into a glass reaction vessel equipped with a mechanical stirrer and reflux condenser. The reaction mixture is heated at reflux for a period of about l5 minutes. After this time the mixture is stripped of benzene under reduced pressure to yield a solid product as the residue. The residue is then recrystallized to yield the desired product the dimethyl acetal of 2-[1- ethyl-3-(5-methoxy-l,3,4-thiadiazol-2-yl) ureido] acetaldehyde.

EXAMPLE 16 Preparation of l-( 5 -Methoxy-l ,3 ,4-thiadiazol-2-yl )-3-ethyl-5- hydroxy-l ,3-imidazolidin-2-one The dimethyl acetal of 2-[ l-ethyl-3-(5-methoxy- 1,3,4-thiadiazol-2-yl) ureido] acetaldehyde grams), water (400 ml) and hydrochloric acid (4 ml) are charged into a glass reaction vessel equipped with a mechanical stirrer, thermometer and reflux condenser. The reaction mixture is heated at reflux for a period of about 15 minutes. The reaction mixture is then filtered while hot and the filtrate is cooled to form a precipitate. The precipitate is recovered by filtration, is dried and is recrystallized to yield the desired product l-(5- methoxy-l ,3 ,4-thiadiazol-2-yl)-3-ethyl-5-hydroxy-l ,3- imidazolidin-Z-one.

EXAMPLE 17 Preparation of l-( S-Methoxy-l ,3 ,4-thiadiazol-2-yl )-3-ethyl-5-[ N- (3 ,4-dichlorophenyl) carbamoyloxyll ,3-imidazolidin-2-one l-( S-Methoxy-l ,3 ,4-thiadiazol-2-yl)-3-ethyl-5- hydroxy-l,3-imidazolidin-2-one (0.05 mole) and 3,4- dichlorophenyl isocyanate (0.06 mole) are charged into a glass reaction vessel. The mixture is stirred until homogeneous and triethylarnine (1 drop) is added. The mixture is then allowed to stand for about 1 hour. After this time the resulting product is washed with hexane and is recrystallized to yeild the desired product l-(S- methoxy-l ,3,4-thiadiazol-2-yl)-3ethyl-5-[N-(3,4- dichlorophenyl) carbamoyloxy1- l ,3-imidazolidin- 2-one.

EXAMPLE 18 Preparation of S-Methylthio-l,3,4-thiadiazol-2-yl lsocyanateDimer A saturated solution of phosgene is ethyl acetate (100 ml) is charged into a glass reaction vessel equipped with a mechanical stirrer. A slurry of S-methylthio-2-amino-l ,3,4-thiadiazole (45 grams) in ethyl acetate (300 ml) is added to the reaction vessel and the resulting mixture is stirred for a period of about l6 hours, resulting in the formation of a precipitate. The reaction mixture is then purged with nitrogen gas to remove unreacted phosgene. The purged mixture is filtered to recover the precipitate. The precipitate is then recrystallized to yield the desired product S-methylthio-l ,3,4-thiadiazol-2-yl isocyanate dimer.

EXAMPLE l9 Preparation of the Dimethyl Acetal of 2-[ l -Propyl-3-(5-methylthiol ,3,4-thiadiazol-2- yl)ureido] acetaldehyde A mixture of S-methylthio-l,3,4-thiadiazol-2 yl isocyanate dimer (0.05 mole), the dimethyl acetal of 2- propylaminoacetaldehyde (0.1 mole) and benzene ml) are charged into a glass reaction vessel equipped with a mechanical stirrer and reflux condenser. The reaction mixture is heated at reflux for a period of about l5 minutes. After this time the mixture is stripped of benzene under reduced pressure to yield a solid product as the residue. The residue is then recrystallized to yield the desired product the dimethyl acetal of 2-[ lpropyl-3-(5-methylthio-l ,3,4-thiadiazol-2-yl)ureido] acetaldehyde.

EXAMPLE 20 Preparation of l-( S-Methylthio-l ,3 ,4-thiadiazol-2-yl )-3-propyl-5- hydroxy-l ,3-imidazolidin-2-one The dimethyl acetal of 2 -[1 -propyl-3-(5-methylthiol,3,4-thiadiazol-2-yl)ureido] acetaldehyde (15 grams), water (400 ml) and hydrochloric acid (4 ml) are charged into a glass reaction vessel equipped with a mechanical stirrer, thermometer and reflux condenser. The reaction mixture is heated at reflux for a period of about 15 minutes. The reaction mixture is then filtered while hot and the filtrate is cooled to form a precipitate. The precipitate is recovered by filtration, is dried and is recrystallized to yield the desired product l-(5- methylthio-l ,3 ,4-thiadiazol-2-yl )-3-propyl-5-hydroxy- 1,3-imidazolidin-2-one.

EXAMPLE 21 Preparation of l-( S-Methylthio-l ,3 ,4-thiadiazol-2-yl )-3-propyl-5 (N,N-dimethylcarbamoyloxy )-l ,S-imidazolidin-Z-one EXAMPLE 22 Preparation of S-Methylsulfonyl-l,3,4-thiadiazol-2-yl Isocyanate Dimer A saturated solution of phosgene in ethyl acetate (I ml) is charged into a glass reaction vessel equipped with a mechanical stirrer. A slurry of 5- methylsulfonyl-Z-amino-l,3,4-thiadiazole (50 grams) in ethyl acetate (300 ml) is added to the reaction vessel and the resulting mixture is stirred for a period of about 16 hours, resulting in the formation of a precipitate. The reaction mixture is then purged with nitrogen gas to remove unreacted phosgene. The purged mixture is then filtered to recover the precipitate. The precipitate is then recrystallized to yield the desired product 5- methylsulfonyl-l,3,4-thiadiazol-2-yl isocyanate dimer.

EXAMPLE 23 Preparation of the Dimethyl Acetal of 2-[ l-Methyl-3-(S-methylsulfonyl-l ,3,4-thiadiazol-2- yl)ureido] acetaldehyde A mixture of S-methylsulfonyl-l,3,4-thiadiazol-2-yl isocyanate dimer (0.05 mole), the dimethyl acetal of 2-methyl-aminoacetaldehyde (0.] mole) and benzene (60 ml) are charged into a glass reaction vessel equipped with a mechanical stirrer and reflux condenser. The reaction mixture is heated at reflux for a period of about minutes. After this time the mixture is stripped of benzene under reduced pressure to yield a solid product as the residue. The residue is then recrystallized to yield the desired product the dimethyl acetal of 2-[l-methyl-3-(S-methylsulfonyl-l,3,4- thiadiazol-2-yi)ureido] acetaldehyde.

EXAMPLE 24 Preparation of l-( S-Methylsulfonyl-i ,3 ,4-thiadiazol-2-yl )-3-methyl-5- hydroxy-l ,3-imidazolidin-2-one The dimethyl acetal of 2-[l-methyl-3-(5-methylsulfonyl-l ,3,4-thiadiazol-2-yl)ureido] acetaldehyde 15 grams), water (400 ml) and hydrochloric acid (4 ml) are charged into a glass reaction vessel equipped with a mechanical stirrer, thermometer and reflux condenser. The reaction mixture is heated at reflux for a period of about l5 minutes. The reaction mixture is then filtered while hot and the filtrate is cooled to form a precipitate. The precipitate is recovered by filtration, is dried and is recrystallized to yield the desired product l-(S- methylsulfonyl-l ,3,4-thiadiazol-2-yl)-3-methyl-5- hydroxyl 3-imiclazolidin-2-one.

EXAMPLE 25 Preparation of I-(S-Methylsulfonyll ,3,4-thiadiazol-2-yl)-3-methyl-5- [N-rnethyl-N-(3-chlorophenyl) carbamoyloxyl-l ,3-imidazolidin-2-one l-(S-Methylsulfonyl-l ,3,4-thiadiazol-2-yl)-3-methyl- S-hydroxy-l,3-imidazolidin-2-one (0.05 mole), N- methyl-N-(4-chlorophenyl)carbamoyl chloride (0.06 mole), pyridine (0.06 mole) and toluene (125 ml) are charged into a glass reaction vessel equipped with a mechanical stirrer, thermometer and reflux condenser. The reaction mixture is heated at reflux with stirring for a period of about 3 hours. After this time the reaction mixture is cooled to room temperature and is filtered to remove pyridine hydrochloride. The filtrate is then washed with water, dried over anhydrous magnesium sulfate and and stripped of solvent leaving a residue. The residue is recrystallized to yield the desired product 1-(5-methylsulfonyl-l,3,4-thiadiazol-2-yl)-3-methyl-5 N-methyl-N-( 3-chlorophenyl )-carbamoyloxy]- 1,3-imidazolidin-2-one.

EXAMPLE 26 Preparation of S-Methylsulfinyl-l,3,4-thiadiazol-2-yl lsocyanate Dimer EXAMPLE 27 Preparation of the Dimethyl Acetal of 2-[ l-Methyl-3-(S-methylsulfinyl-l ,3,4-thiadiazol-2- yl)ureido] acetaldehyde A mixture of 5-methylsulfinyl-1,3,4-thiadiazol-2-yl isocyanate dimer (0.05 mole), the dimethyl acetal of 2-methyl-aminoacetaldehyde (0.1 mole) and benzene (60 ml) are charged into a glass reaction vessel equipped with a mechanical stirrer and reflux condenser. The reaction mixture is heated at reflux for a period of about 15 minutes. After this time the mixture is stripped of benzene under reduced pressure to yield a solid product as the residue. The residue is then recrystallized to yield the desired product the dimethyl acetal of 2-[ l-methyl-3-( S-methylsulflnyll ,3 ,4- thiadiazol-Z-yl)ureidol-acetaldehyde.

EXAMPLE 28 Preparation of l-( S-Methylsulfinyl-l ,3 ,4-thiadiazol-2-yl )-3-methyl-5- hydroxy-l ,3-imidazolidin-2-one The dimethyl acetal of 2-[ l-rnethyl-3-(S-methylsulfinyll ,3,4-thiadiazol-2-yl)ureido] acetaldehyde (l5 grams), water (400 ml) and hydrochloric acid (4 ml) are charged into a glass reaction vessel equipped with a mechanical stirrer, thermometer and reflux condenser. The reaction mixture is heated at reflux for a period of about 15 minutes. The reaction mixture is then filtered while hot and the filtrate is cooled to form a precipitate. The precipitate is recovered by filtration, is dried and is recrystallized to yield the desired product l-(S- methylsulfinyl-l ,3,4-thiadiazol-2-yi)-3-methyl-5- hydroxy-l ,3-imidazolidin-2-one.

EXAMPLE 29 Preparation of I-(S-Methylsulfinyl-l ,3 ,4-thiadiazol-2-yl)-3-methyl-5- (N-methyl-N-cyclohexylcarbamoyloxy)-l ,3-imidazolidin-Z-one I-(S-Methylsulflnyl-l ,3,4-thiadiazol-2-yl)-3-methyl- S-hydroxy-l,B-imidazolidin-Z-one (0.05 mole), N- methyl-N-cyclohexylcarbamoyl chloride (0.06 mole), pyridine(0.06 mole) and toluene ml) are charged into a glass reaction vessel equipped with a mechanical stirrer, thermometer and reflux condenser. The reaction mixture is heated at reflux with stirring for a period of about 3 hours. After this time the reaction mixture is cooled to room temperature and is filtered to remove pyridine hydrochloride. The filtrate is then washed with water, dried over anhydrous magnesium sulfate and stripped of solvent leaving a residue. The residue is recrystallized to yield the desired product l-(S-methylsulfinyl-l ,3 ,4-thiadiazol-2-yl )-3-methyl-5-(N-methyl- N-cyclohexylcarbamoyloxy )-l ,3-imidazolidin-2-one.

EXAMPLE 30 Preparation of I-(S-t-Butyl-l ,3,4-thiadiazol-2-yl)-3-methyl-5-carbamoyloxy-l ,3-imidazolidin-2-one l-( S-t-Butyl-l ,3,4-thiadiazol-2-yl)-3-methyl-5- hydroxy-l,3-imidazolidin-2-one (0.05 mole) dispersed in concentrated aqueous acetic acid (90% concentration', l25 ml) is charged into a glass reaction vessel equipped with a mechanical stirrer. The reaction mixture is stirred at room temperature and powdered potassium cyanate (0.06 mole) is incrementally added over a period of minutes. After the addition is completed stirring is continued for a period of about 1 hour to ensure completion of the reaction. After this time the reaction mixture is filtered to recover the product that has formed. This product is then washed with dilute aqueous potassium carbonate and with water and is then recrystallized to yield the desired product l-(S- t-butyl-l ,3 ,4-thiadiazol-2-yl)-3-methyl-S-carbamoyloxy-l ,3-imidazolidin-2-one.

EXAMPLE 31 Preparation of l-( S-Methyl-l ,3,4-thiadiazol-2-yl)-3-methyl-5-(N- methylthiocarbamoyloxy )-l ,B-imidazolidin-Z-one l-( S-Methyll ,3,4-thiadiazol-2-yl)-3-methyl-5- hydroxy-l,3-imidazolidin-2-one (0.05 mole) and methyl isothiocyanate (3.5 ml; 0.06 mole) arecharged into a glass reaction vessel equipped with a mechanical stirrer. The mixture is stirred and triethylamine (I drop) is added. The reaction mixture is then allowed to stand for a period of about 1 hour. After this time the product is washed with hexane to yield the desired product l-( S-methyl-l ,3,4-thiadiazol-2-yl)-3-methyl-5- (N-methylthiocarbamoyloxy )-l ,3-imidazolidin-2-one.

EXAMPLE 32 Preparation of 1-( S-t-Butyl-l ,3,4-thiadiazol-2-yl)-3-methyl-5-(N- methylthiocarbamoyloxy)-l ,3-imidazolidin-2-one l-( S-t-Butyl-l ,3 ,4-thiadiazol-2-yl)-3-methyl-5- hydroxy-l,3-imidazolidin-2-one (4 grams) and methyl isothiocyanate 5 ml) are charged into a glass reaction vessel equipped with a mechanical stirrer. The mixture is stirred until homogeneous and triethylamine (1 drop) is added thereto. The reaction mixture is then stripped of excess isothiocyanate and the remaining solid is recrystallized to yield the desired product l-(5- t-butyl-l ,3 ,4-thiadiazol-2-yl)-3-methyl-5-(N-methylthiocarbamoyloxy)- l ,3-imidazolidin-2-one.

EXAMPLE 33 Preparation of 1 -(5-Trifluoromethy1-l ,3,4-thiadiazol-2-yl)-3-methyl- 5-( N-phenylthiocarbamoyloxy)- l ,3-imidazolidin-2-one l -(5-Trifluor0methyl-l ,3,4-thiadiazol-2-yl )-3-methyl-5-hydroxy-l ,3-imidazolidin-2-one (4 grams) and phenyl isothiocyanate are charged into a glass reaction vessel. The mixture is stirred until homogeneous and triethylamine (1 drop) is added. The mixture is then allowed to stand for 5% hour. After this time the resulting product is washed with hexane and is then recrystallized to yield the desired product l-(S-trifluoromethyll,3,4-thiadiazol-2-yl)-3 -methyl-S-(N-phenylthiocarbamoyloxy)-l ,3-imidazolidin-2-one.

EXAMPLE 34 Preparation of l-( S-Mcthoxyl ,3,4-thiadiazol-2-yl)-3-ethyl-5-[ N- (3,4-dichllorophenyl)thiocarbamoyloxy1-I ,3-

imidazolidin-Z-one l-( S-Methoxyl ,3,4-thiadiazol-2-yl )-3-ethyl-5- hydroxy-l ,3-imidazolidin-2-one (0.05 mole) and 3 ,4- dichlorophenyl isothiocyanate (0.06 mole) are charged into a glass reaction vessel. The mixture is stirred until homogeneous and triethylamine (I drop) is added. The mixture is then allowed to stand for about I hour. After this time the resulting product is washed with hexane and is recrystallized to yield the desired product l-(S- methoxy-l ,3,4-thiadiazol-2-yl )-3-ethyl-5-[N-( 3 ,4- dichlorophenyl)thiocarbamoyloxy]-l ,S-imidazolidin- 2-one.

EXAMPLE 35 Preparation of l-( S-Methylthiol ,3 ,4-thiadiazol-2-yl )-3-propyl-5 (N,N-dimethylthiocarbamoyloxy)-l ,3-imidazolidin- 2-one I-(S-Methylthio-l ,3,4-thiadiazol-2-yl)-3-propyl-5- hydroxy-l ,3-imidazolidin-2-one (0.05 mole), N,N- dimethylthiocarbamoyl chloride (0.06 mole), pyridine (0.06 mole) and xylene ml) are charged into a glass reaction vessel equipped with a mechanical stirrer, thermometer and reflux condenser. The reaction mixture is heated at reflux with stirring for a period of about 2 hours. After this time the mixture is cooled to room temperature and filtered to remove pyridine hydrochloride. The filtrate is then stripped of solvent under reduced pressure and the resulting residue is recrystallized to yield the desired product l-(S-methylthio-l ,3 ,4-thiadiazol-2-yl )-3-propyl-5-( N ,N-dimethylthiocarbamoyloxy)-1,3-imidazolidin-2-one.

Additional compounds within the scope of the present invention which can be prepared by the procedures detailed in the foregoing examples are l-(S-ethyl-l ,3,4 thiadiazol-2-yl)-3-methyl-5-(N-ethylcarbamoyloxy)- l,3-imidazolidin-2-one, l-(S-isopropyl-l ,3 ,4- thiadiazol-Z-yl)-3-butyl-5-(N-propylcarbamoyloxy)- l,3-imidazolidin-2-one, l-(5-hexyl-l ,3 ,4-thiadiazol-2- yl)-3-hexyl-5-(N-hexylcarbamoyloxy)-l ,S-imidazolidin-Z-one, l-(5-allyll ,3 ,4-thiadiazol-2-yl)-3-methyl-5- (N-cyclopropylcarbamoyloxy)-l ,3-imidazolidin-2-one, 1-( S-pent-3-enyl-l ,3,4-thiadiazol-2-yl)-3-methyl-5-( N- cyclobutylcarbamoyloxy)-l ,3-imidazolidin-2-one, l (5-hex-4-enyl-l ,3,4-thiadiazol-2-yl)-3-methyl-5-(N- cyclopentylcarbamoyloxy)-1,B-imidazolidin-Z-one, l-

(S-B-chloroethyl-l ,3,4-thiadiazol-2-yl)-3-methyl-5-(N- cycloheptylcarbamoyloxy )-l ,B-imidazolidin-Z-one, l- (5-y-bromopropyll ,3 ,4-thiadiazol-2-yl )-3-methyl-5- (N ,N-diethylcarbamoyloxy 1 ,S-imidazolidin-Z-one, l( 5-ethoxy-l ,3 ,4-thiadiazol-2-yl)-3-methyl-5-[N-(2- methylphenyl)carbamoyloxy1-l,3-imidazolidin-2-one, l-(5-propoxy-1,3 ,4-thiadiazol-2-yl)-3-methyl-5-[N-( 2- ethylphenyl)carbamoyloxy]-l ,3-imidazolidin-2'one, l S-hexyloxy-l ,3,4-thiadiazol-2-yl)-3-methyl- S-[N- (4-butylphenyl)carbamoyloxy]-l ,B-imidazolidin- 2-one, l-( 5-ethylthio-l ,3,4-thiadiazol-2-yl)-3-methyl- 5-[ N-(4-hexylphenyl )-carbamoyloxy l ,3-imidazolidin-Z-one, I-(S-butylthio-l ,3,4-thiadiazol-2-yl)-3- methyl-5-[N-( 2,4-dimethylphenyl)carbamoyloxyl-l ,3- imidazolidin-Z-one, l-(5-hcxylthio-l ,3,4-thiadiazol-2- yl)-3-methyl-5-[N(4-bromophenyl)carbamoyloxy]- l ,3-imidazolidin-2one, l-(S-methylsulfonyl-l ,3,4- thiadiazol-Z-yl)-3-methyl-5-[N-(4-iodophenyl)carbamoyloxyll ,3-imidazolidin-2-one, l-( S-ethylsulfonyl-l ,3,4-thiadiazol-2-yl)-3-methyl-5-[N-(4-fluorophenyl)carbamoyloxy]-l ,3-imidazolidin-2-one, l-( 5- propylsulfonyl-l ,3,4-thiadiazol-2-yl)-3-methyl-5-[N- (4-trifluoromethyphenyl )carbarnoyloxy1- l ,3- imidazolidinQ-one, l -(5-hexylsulfonyl-l ,3,4- thiadiazol-Z-yl)-3-methyl-5-[N-(4-trichloromethylphenyl)carbamoyloxy]-l ,3-imidazolidin-2-one, 1-( 5- ethylsulfinyl-l ,3,4-thiadiazol-2-yl )-3-methyl-5-[N-( 2- methoxyphenyl)carbamoyloxy]-l ,S-imidazolidin- 2-one, l-( S-propylsulfinyl-l ,3 ,4-thiadiazol-2-yl)-3- methyl-5-[N-(Z-ethoxyphenyl)carbamoyloxy]-l ,3- imidazolidin-2-one, l-(5-butylsulfinyl-l ,3 ,4-thiadiazol- 2-yl )-3-methyl-5-{N-( 3-propoxyphenyl)carbamoyloxyl-l ,3-imidazolidin-2-one, I-(S-hexylsulfinyl-l ,3,4- thiadiazol-Z-yl)-3-methyl-5-[N-(S-hexyioxyphenyl)- carbamoyloxyl-l ,3-imidazolidin-2-one, 1-( S-t-butylsulfinyl-l ,3 ,4-thiadiazol-2-yl)-3-methyl-5-[N-(2,4,6- trichlorophenyl )carbamoyloxy1- l ,3 -imidazolidin- 2-one, l-(S-hexyl-l,3,4-thiadiazol-2-yl)-3-hexyl5-(N- hexylthiocarbamoyloxy-l ,3-imidazolidin-2-one, l-( 5- hex-4-enyll ,3 ,4-thiadiazol-2-yl )-3-methyl-5 N- cyclopentylthiocarbamoyloxy )-l ,B-imidazolidin-Z-one, l-(5-ethoxy-1,3,4-thiadiazol-2-yl)-3-methyl5-[N-(2- methylphenyl)thiocarbamoyloxy]-l ,3-imidazolidin- 2-one, l-(S-ethylthio-l ,3,4-thiadiazol-2-yl)-3-methyl- 5-[N-(4 -hexylphenyl)thiocarbamoyloxy1-1,3- imidazolidin-Z-one, l-( S-methylsulfonyl-l ,3,4- thiadiazol-Z-yl)-3-methyl-5-[N-(4-iodophenyl)thiocarbamoyloxyl-l ,3-imidazolidin-2-one, I-(S-hexylsulfonyl-l ,3,4-thiadiazol-2-yl)-3-methyl-5-[N-(4-trichloromethylphenyl)-thiocarbamoyloxy]-l ,3- imidazolidin-Z-one, l-( 5-butyllsulfinyll ,3 ,4- thiadiazol-Z-yl)-3-methyl-5[N-(3-propoxyphenyl)thiocarbamoyloxyl-l ,B-irnidazolidin-Z-one.

For practical use as herbicides the compounds of this invention are generally incorporated into herbicidal compositions which comprise an inert carrier and a herbicidially toxic amount of such a compound. Such herbicidal compositions, which can also be called formulations, enable the active compound to be applied conveniently to the site of the weed infestation in any desired quantity. These compositions can be solids such as dusts, granules, or wettable powders; or they can be liquids such as solutions, aerosols, or emulsifiable concentrates.

For example, dusts can be prepared by grinding and blending the active compound with a solid inert carrier such as the tales, clays, silicas, pyrophyllite, and the like. Granular formulations can be prepared by impregnating the compound, usually dissolved in a suitable solvent, onto and into granulated carriers such as the attapulgites or the vermiculites, usually of a particle size range of from about 0.3 to 1.5 mm. Wettable powders, which can be dispersed in water or oil to any desired concentration of the active compound, can be prepared by incorporating wetting agents into concentrated dust compositions.

In some cases the active compounds are sufficiently soluble in common organic solvents such as kerosene or xylene so that they can be used directly as solutions in these solvents. Frequently, solutions of herbicides can be dispersed under super-atmospheric pressure as aerosols. However, preferred liquid herbicidal compositions are emulsifiable concentrates, which comprise an active compound according to this invention and as the inert carrier, a solvent and an emulsifier. Such emulsifiable concentrates can be extended with water and/or oil to any desired concentration of active compound for application as sprays to the site of the weed infestation. The emulsifiers most commonly used in these concentrates are nonionic or mixtures of nonionic with anionic surface-active agents. With the use of some emulsifier systems an inverted emulsion (water in oil) can be prepared for direct application to weed infestations.

A typical herbicidal composition according to this invention is illustrated by the following example, in which the quantities are in parts by weight.

EXAMPLE 36 The above ingredients are mixed in a mechanical grinder-blender and are ground until a homogeneous, free-flowing dust of the desired particle size is obtained. This dust is suitable for direct application to the site of the weed infestation.

The compounds of this invention can be applied as herbicides in any manner recognized by the art. One method for the control of weeds comprises contacting the locus of said weeds with a herbicidal composition comprising an inert carrier and as an essential active ingredient, in a quantity which is herbicidally toxic to said weeds, a compound of the present invention. The concentration of the new compounds of this invention in the herbicidal compositions will vary greatly with the type of formulation and the purpose for which it is designed, but generally the herbicidal compositions will comprise from about 0.05 to about percent by weight of the active compounds of this invention. in a preferred embodiment of this invention, the herbicidal compositions will comprise from about 5 to about 75 percent by weight of the active compound. The compositions can also comprise such additional substances as other pesticides, such as insecticides, nematocides, fungicides, and the like; stabilizers, spreaders, deactivators, adhesives, stickers, fertilizers, activators, synergists, and the like.

The compounds of the present invention are also useful when combined with other herbicides and/or defoliants, dessicants, growth inhibitors, and the like in the herbicidal compositions heretofore described. These other materials can comprise from about 5% to about 95% of the active ingredients in the herbicidal compositions. .Use of combinations of these other herbicides and/or defoliants, dissicants, etc. with the compounds,

such as CDEC, metham sodium, EPTC, diallate, PEBC,

perbulate, vernolate and the like; substituted urea herbicides such as norea, siduron, dichloral urea, chloroxuron, cycluron, fenuron, monuron, monuron TCA, diuron, linuron, monolinuron, neburon, buturon, trimeturon and the like; symmetrical triazine herbicides such as simazine, chlorazine, atraone, desmetryne, norazine, ipazine, prometryn, atazine, trietazine, simetone, prometone, propazine, ametryne and the like; chloroacetamide herbicides such as alpha-chloro-N, N- dimethylacetamide, CDEA, CDAA, alpha-chloro-N- isopropylacetamide, 2-chloro-N-isopropylacetanilide,,

4-(chloroacetyl)morpholine, l-(chloroacetyl) piperidine, and the like; chlorinated aliphatic acid herbicides such as TCA, dalapon, 2,3-dichloropropionic acid, 2,2,3-TPA and the like; chlorinated benzoic acid and phenylacetic acid herbicides such as 2,3,6-TBA, 2,3,5,6-TBA, tricamba; amiben, fenac, PBA, 2- methoxy-3,6-dichlorophenylacetic acid, 3-methoxy- 2,6-dichlorophenylacetic. acid, 2-methoxy-3,5,6-trichlorophenylacetic acid, 2,4 dichloro-3-nitrobenzoic acid and the like; and such compounds as aminotriazole, maleic hydrazide, phenyl mercuric acetate, endothal, biuret, technical chlordane, dimethyl 2,35,6- tetrachloroterephthalate, diquat, erbon, DNC, DNBP, dichlobenil, DPA, diphenamid, dipropalin, trifluralin, solan, dicryl, merphos, DMPA, DSMA, MSMA, potassium azide, acrolein, benefin, bensulide, AMS, bromaoil, 2( 3,4-dichlorophenyl)-4-methyl-1 ,2 ,4-oxadiazolidine-3,5-dione, bromoxynil, cacodylic acid, CMA, CPMF, cypromid, DCB, DCPA, dichlone, diphenatril, DM'I'I, DNAP, EBEP, EXD, l-lCA, ioxynil, lPX, isocil, potassium cyanate, MAA, MAMA, MCPES, MCPP, MH, molinate, NPA, QCH, paraquat, PCP, picloram, DPA, PCA, pyrichlor, sesone, terbac il, terbutol, TCBA, brominil, CP-50l44, H-l76-l, H-732, M-290l, planavin, sodium tetraborate, calcium cyanamid, DEF, ethyl xanthogen disulfide, sindone, sindone B, propanil and the like.

Such herbicides can also be used in the methods and compositions of this invention in the form of their salts, esters, amides, and other derivatives whenever applicable to the particular parent compounds.

Weeds are undesirable plants growing where they are not wanted, having no economic value, and interfering with the production of cultivatedcrops, with the growing of ornamental plants, or with the welfare of livestock. Many types of weeds are known, including annuals such as pigw eed, lambsquarters, foxtail, crabgrass, wild mustard, field pennycress, ryegrass, goose-grass,

chickweed, wild oats, velvetleaf, purslane, barnyard grass, smartweed, knotweed, cocklebur, wild buckwheat, kochia, medic, corn cockle, ragweed, sowthistle, coffeeweed, croton, cuphea, dodder, fumitory,

groundsel, hemp nettle, knawel, spurge, spurry, emex, jungle rice, pondweed, dog fennel, carpetweed, morning glory, bedstraw, ducksalad, naiad, cheatgrass, fall panicum, jimsonweed, witchgrass, switchgrass, watergress, teaweed, wil turnip and sprangletop; biennials such as wild carrot, matricaria, wild barley, campion, chamomile, burdock, mullein, roundleaved mallow, bull thistle, hounds-tongue, moth mullein and purple star thistle; or perennials such as white cockle, perennial ryegrass, quackgrass, Johnson grass, Canada thistle, hedge bindweed, Bermuda grass, sheep sorrel, curly dock, nutgrass, field chickweed, dandelion, campanula, field bindweed, Russian knapweed, mesquite, toadflax, yarrow, aster, gromwell, horsetail, ironweed, sesbania, bulrush, cattail, winter-cress, horsenettle, nutsedge, milkweed and sicklepod.

Similarly, such weeds can be classified as broad-leaf or grassy weeds. It is economically desirable to control the growth of such weeds without damaging beneficial plants or livestock.

The new compounds of this invention are particularly valuable for weed control because they are toxic to many species and groups of weeds while they are relatively non-toxic to many beneficial plants. The exact amount of compound required will depend on a variety of factors, including the hardiness of the particular weed species, weather, type of soil, method of application, the kind of beneficial plants in the same area, and the like; Thus, while the application of up to only about I or 2 ounces of active compound per acre may be sufficient for good control of a light infestation of weeds growing under adverse conditions, the application of ten pounds or more of an active compound per acre may be required for good control of a dense infestation of hardy perennial weeds growing under favorable conditions.

The herbicidal toxicity of the new compounds of this invention can be illustrated by many of the established testing techniques known to the art, such as preand post-emergence testing.

The herbicidal activity of the compounds of this invention was demonstrated by experiments carried out for the pre-emergence control of a variety of weeds. in these experiments small plastic greenhouse pots filled with dry soil were seeded with the various weed seeds. Twenty-four hours or less after seeding the pots were sprayed with water until the soil was wet and the test compounds formulated as aqueous emulsions of acetone solutions containing emulsifiers were sprayed at the indicated concentrations on the surface of the soil.

After spraying, the soil containers were placed in the greenhouse and provided with supplementary heat as required and daily or more frequent watering. The plants were maintained under these conditions for a period of from 15 to 21 days, at which time the condition of the plants and the degree of injury to the plants was rated on a scale of from 0 to [0, as follows: 0 no injury, 1, 2 slight injury, 3, 4 moderate injury, 5, 6 moderately severe injury, 7, 8, 9 severe injury and 10 death. The effectiveness of these compounds is demonstrated by the following data:

TABLE 1 Test Concentration lNJURY RATING Com- (lbs/acre) pound of Compound YNSG WOAT JMWD VTLF .lNGS PIGW MSTD YLFX WRGS CBGS CTGS MNGY BNGS Pr 10 9.5 9.5 9.0 9 0 9.5 10 10 9.5 9.5 l0 l0 l0 duct of 2 l0 l0 9.5 10 l0 l0 10 9.5 l0 l0 10 9.5 Ext. 8 l l0 10 9.5 10 9.5 l0 10 9.5 10 l0 10 9.5

Pro- 7.5 8.5 9.5 [0 8.0 9.5 l0 9.5 9.0 10 l0 l0 duct of 4 2.5 5.0 9.5 10 4.5 l0 10 9.5 9.0 7.5 4.0 Ex. 12 2 0 1.0 7.5 7.5 0 9.0 9.5 1.0 7.0 4.0 1.0

Pro- 10 8.5 9.0 l0 9.5 5.0 9.5 10 10 9.5 25 l0 l0 duct of 4 0 9.5 l0 l0 l0 10 9.5 9.5 6.0 1.0

Values are averages of two or more replicates YNS/G Yellow Nutsedge JN .lohnsongrass CBGS Crabgrass \VOAT Wild Oats PIGW Pigweed CTGS Cheatgrass J M W D .l imsonweed MSTD M ustard MNG Y Momin lory VTLF Velvet Leaf YLFX Yellow Foxtail BNGS Barnyar grass WRGS Watergrass The herbicidal activity of the compounds of this in- I claim:

vention was also demonstrated by experiments carried out for the post-emergence control of a variety of weeds. ln these experiments the compounds to be tested were formulated as aqueous emulsions and sprayed at the indicated dosage on the foliage of the weeds that have attained a prescribed size. After spraying the plants were placed in a greenhouse and watered daily or more frequently. Water was not applied to the foliage of the treated plants. The severity of the injury was determined 10 to days after treatment and was rated on the scale of from 0 to 10 heretofore described. The effectiveness of these compounds is demonstrated by the following data:

l. A compound of the formula 5 wherein R is selected from the group consisting of TABLE 11 Concentration INJURY RATING (lbs/acre) Test of Compound Compound YNSG WOAT JMWD VTLF JNGS PIGW MSTD YLFX WRGS Product of l0 l0 l0 l0 l0 l0 l0 l0 10 Example 8 2 l0 l0 l0 10 10 l0 l0 1/2 l0 l0 I0 9 0 l0 10 8.5 1116 0 9.0 6.0 15 L0 10 0 Product of 10 0 3 l0 2 S 10 0 2 Example 12 4 l0 9 l0 Product of 10 0 8 l0 0 4 9 0 0 Example 13 4 l0 l0 l0 Concentration (lbmleere) Test of Compound Compound C808 CTGS MNGY BDWD BNGS LMQR COFW CKBR BKWT Product of l0 l0 10 t0 Example 8 2 9.5 10 9.5 10

Product of 10 0 3 6 Example 12 4 l0 9 3 10 Product of IO 0 2 0 3 Example 13 4 10 9 l 10 Values ma be avera es of two replicates YNGS y Yellow Nutledge MSTD Multard BDWD Btndweed WOAT Wild Oats YLFX Yellow Foxtall BNGS Barnyardgrau .IMWD Jimronweed WRGS Watergrass LMQR Lambsqunrter VTLF Velvet Leaf CBGS Crabgrasl COFW Cofl'eeweed JNGS Johnrongras CTGS Cheatgrasl CKBR Cocklebur PIGW Pigweed MNGY Morningglory BKWT Buckwheat 21 22 kylsulfinyl; R is lower alkyl R is selected from the The compound of Claim y group consisting of hydrogen and lower alkyl; Y is sef q -y y y y)- lected from the group consisting of oxygen and sulfur;

3. The compound of claim 1, l-(5-t-butyl-1,3,4- 5 thiadiazol-Z-yl)-3-methyl-5-(N-methylcarbamoyloxy)- 1,3-imidazolidin-2-one.

4. The compound of claim I, l-(5-trifluoromethyl- 1,3 ,4-thiadiazol-2-yU-3 -methyl-5-(N-methylcarbamoyloxy)-l ,3-imidazolidin-2-one. X 5. The compound of claim 1, l-(5-trifluormethyln 1,3 ,4-thiadiazol-2-yl)3 -methyl-5-( Nphenylcarbamoyloxy)-1 ,3-imidazolidin-2-one.

6. The compound of claim 1, l-(5-methoxy-l,3,4- thiadiazol-2-yl)-3-ethyl-5-N-(3,4-dichlorophenyl)car- 5 bamoyloxyl ,S-imidazolidin-Z-one. H 7. The compound of claim I, l-(5-methylthio-l,3,4-

( l thiadiazol-Z-yl )-3 -propyl-SN,N-dimethylcarbamoyloxy)- l ,S-imidazolidin-Z-one. I 8. The compound of claim 1, I-(5-t-butyl-l,3,4- wherein X IS selected from the group consisting of m n 3- 5 l 1 3- lower alkyl, halogen, lower haloalkyl and lower alkoxy, imid o|idi -2- e and n is an integer from 0 to 3.

and R is selected from the group consisting of hydrogen, lower alkyl, cycloalkyl of from 3 to 7 carbon atoms and 

1. A COMPOUND OF THE FORMULA 1-R2,2-(O=),3-(2-R1-1,3,4-THIADIAZOL-5-YL),4-(R3-N(-R4)C(=Y)-O -)IMIDAZOLIDINE WHEREIN R1 IS SELECTED FROM THE GROUP CONSISTING OF LOWER ALKYL, LOWER ALKENYL, LOWER HALOALKYL, LOWER ALKOXY, LOWER ALKYLTHIO, LOWER ALKYSULFONYL AND LOWER ALKYLSULFINYL; R2 IS LOWER ALKYL R3 IS SELECTED FRO THE GROUP CONSISTING OF HYDROGEN AND LOWER ALKYL; Y IS SELECTED FROM THE GROUP CONSISTING OF OXYGEN AND SULFUR; AND R4 IS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN, LOWER ALKYL, CYCLOALKYL OF FROM 3 TO 7 CARBON ATOMS AND
 2. The compound of claim 1, 1-(5-methyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-(N-methylcarbamoyloxy)-1,3 -imidazolidin-2-one.
 3. The compound of claim 1, 1-(5-t-butyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-(N-methylcarbamoyloxy)-1,3 -imidazolidin-2-one.
 4. The compound of claim 1, 1-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-(N -methylcarbamoyloxy)-1,3-imidazolidin-2-one.
 5. The compound of claim 1, 1-(5-trifluormethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-(N-phenylcarbamoyloxy)-1,3-imidazolidin-2-one.
 6. The compound of claim 1, 1-(5-methoxy-1,3,4-thiadiazol-2-yl)-3-ethyl-5-N-(3,4 -dichlorophenyl)carbamoyloxy-1,3-imidazolidin-2-one.
 7. The compound of claim 1, 1-(5-methylthio-1,3,4-thiadiazol-2-yl)-3-propyl-5N,N-dimethylcarbamoyloxy) -1,3-imidazolidin-2-one.
 8. The compound of claim 1, 1-(5-t-butyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-carbamoyloxy-1,3-imidazolidin-2-one. 